Patents Assigned to Dragon Systems UK Limited
  • Methods and apparatus for detecting harmonic structure in a waveform
    Patent number: 5809453
    Abstract: The periodicity of a signal from a voice channel is determined by sampling the signal, computing the log power spectrum, optionally thresholding and differencing the power spectrum, and then performing an autocorrelation function of limited order to confine the search for periodicity to spans of up to about 400 Hz to 500 Hz.
    Type: Grant
    Filed: January 25, 1996
    Date of Patent: September 15, 1998
    Assignee: Dragon Systems UK Limited
    Inventor: Melvyn John Hunt